The unmanned aerial vehicles are equipped with various sensors, such as cameras, and take photos and videos from the air. This makes surveying possible even in hard-to-reach places.
This is an evaluation method. From photographs of an object, its position and shape are indirectly determined by image measurement and its content is described by image interpretation.
If you want to build or operate an airfield refueling system for flammable liquids with a flash point <23°C or make certain changes to it that affect the safety of the system, you must apply for a permit from the responsible authority.